Author Topic: So while driving to work today...transmission fun! - total engine rebuild fun! (Read 9539 times)

MCRider · « **Reply #25 on:** November 24, 2009, 09:52:10 AM »

Thanks for the breakdown Mystic. Good to know.

mystic_1 · « **Reply #26 on:** November 24, 2009, 10:28:43 AM »

I know the K7/K8 have the final drive offset to the left compared to earlier models, but I am not sure about the F models. Cycle Exchange has pics and data:

http://www.cyclexchange.net/Honda%20Page.htm

mystic_1

SKTP · « **Reply #27 on:** November 24, 2009, 10:34:22 AM »

You guys are AWESOME!!!!!

SKTP · « **Reply #28 on:** November 24, 2009, 05:10:36 PM »

More and more questions...Gasket sets

What do you recommend? I don't want to have to do this again for a long, long time...

what do you think of something like this?

http://cgi.ebay.com/ebaymotors/HONDA-CB750-K-F-ENGINE-GASKET-SET-1974---1978_W0QQitemZ380175711619QQcmdZViewItemQQimsxZ20091108?IMSfp=TL0911081810009r2944#ht_2232wt_875

mystic_1 · « **Reply #29 on:** November 24, 2009, 05:27:15 PM »

Never heard of D&K gasket sets, so can't comment on them. I like Vesrah gaskets personally, or stock but you can't get the OE gaskets as a set. Only thing about the Vesrah set is that it lacks the head bolt sealing pucks that go underneath the cam towers. Athena gasket sets include these but the rest of the set seems cheap, particularly the head gasket.

mystic_1

SKTP · « **Reply #30 on:** November 30, 2009, 10:32:57 AM »

So, my tranny is messed up as stated earlier in this thread. I only ride the bike and was considering getting a car loan, buying a car, etc..while I worked on the bike. Now after searching around...I'm thinking of just taking the bike to http://cbrzone.com/sohc.html and having them turn it into 836cc and having them rebuild the engine. Basically I love my bike and want my engine turned into a VERY DEPENDABLE LEAK FREE and SPORTY daily driver...what do you know about APE? Should I just leave it at 750 or is a good 836 bore job a good idea? I think the rebuild would be cheaper than a decent car so I still sort of save money and my bike will last another 40,000 miles

Basically, what do you know about APE? Are they good/worth it...?(they are about an hour or so away from me)...what would you consider a fair price for an engine rebuild? on their site looks like $560 for the kit, $200 for the cam, cam chain + springs, then labor...+ the tranny....I'm calling them soon it all adds up quickly but I think for like 1500ish I'd basically have a brand new engine, instead of a beater car and a messed up bike, right?

edit (I bought a 77 and a 78 tranny off ebay for less than 70 bucks, so I figure they could use those parts for the tranny while the engine was out? Or is this just going to be crazy expensive)

nobody · « **Reply #31 on:** November 30, 2009, 10:41:50 AM »

I think your $1500 estimate is WAAAAAAAAAAAAY below the mark. I was quoted $1000-1500 by several people for a transmission job alone. If you're having the transmission rebuilt and having the engine overbored you should expect somewhere between $2500 and $4000 depending on how much work you have done to the engine guts.

If you want an 836 to run with the power it should you're going to have to break the bank.

If I were you I'd just take a stab at rebuilding the transmission and see what happens, you'll feel a lot more accomplished than if you just wrote a check. Buy a cheap car in the meantime if you need transportation.

MCRider · « **Reply #32 on:** November 30, 2009, 10:45:55 AM »

Big Jay at APE was there when the CB750 came out. In fact i think it may have been the CB750 that got APE going in the first place. I've bot tons of stuff from them over the years. IF they were close to me I'd definitely give them a shot at building any engine I would ever want to ride.

Of course the bread and butter bikes are the Hayabusa and that ilk. Big Jay works on the CB750 not for the money, but out of love. Could probably do it in his sleep. Can't beat that.

As far as price, you may be low, but ask them.

Yoshi823 · « **Reply #33 on:** November 30, 2009, 11:14:54 AM »

Try Carpy at www.cb750cafe.com for the bits.He may well have spare parts or know where to get the parts from.

I have found that the SOHC 750 engine is really easy to work on.Just remove all of the clutch,generator,gearchange etc covers,turn the engine over and remove the lower crankcase.The gear shafts will stay sitting in the upper crankcase.

I have always said...if someone else can do it...then so can I.

SKTP · « **Reply #34 on:** November 30, 2009, 12:13:17 PM »

Yep, looks like taking it apart...APE does not do engine rebuilds or tranny rebuilds, only the custom/mod work

Anyone know any good used car deals in the SoCal area?

SKTP · « **Reply #35 on:** December 01, 2009, 01:55:28 PM »

I was reading some other threads and I have been wondering what changed to cause my tranny to start acting crazy...and I realized that I switched from regular to premium gas for the last little while? Could that have buggered it all up?

Sam Green Racing · « **Reply #36 on:** December 01, 2009, 02:35:41 PM »

No and I think the later Fs had larger output shaft bearings but the K8 may be the same bottom end.

Sam.

TwoTired · « **Reply #37 on:** December 01, 2009, 03:30:06 PM »

Quote from: SKTP on December 01, 2009, 01:55:28 PM

I was reading some other threads and I have been wondering what changed to cause my tranny to start acting crazy...and I realized that I switched from regular to premium gas for the last little while? Could that have buggered it all up?

No.
Regular and premium have the same energy content. Premium just has additives to delay ignition with heat. Power gains from premium fuel alone are mere myth. Yes, engines made to require premium make more power. But, it is NOT because of the fuel, but the engine parameters that make premium fuel a requirement.

nobody · « **Reply #38 on:** December 01, 2009, 03:33:25 PM »

My guess is that something was probably weakened previously and the low end torque of your start just gave it the finishing push and it broke. What that might be, I'm not certain. I'm still trying to diagnose my stupid transmission problem.

SKTP · « **Reply #39 on:** December 01, 2009, 04:10:28 PM »

I'm getting really good at starting in second...

SKTP · « **Reply #40 on:** December 02, 2009, 10:09:22 AM »

Maybe I should star a new thread but here goes: the Laundry List:

I need to fix my transmission I bought a 77 and 78 off ebay. I figure I can make 1 good one out of one or both. Since the engine is coming out and apart, I figure I should rebuild/clean/replace/paint as much as I can afford here's what I'd like to do if money and skill allow...please feel free to suggest what I should do and will need...thanks

- engine out/clean/paint
  - impact driver

- full engine gasketset (cycle X?)

- new cam/rings/valves
  - ring compressor
  - torque wrench

- new cam, chain and tensioner

- have the frame powder coated

what else should I do while I'm in there? What are obvious things that I will need to do? Tools, parts, etc...please help, thanks

yes, this will be the first major engine work I have ever done

EverettShadowbrook · « **Reply #41 on:** December 02, 2009, 01:40:53 PM »

NICE SKTP! Doing it yourself. That's what I like to hear. Can I help? I'm good a taking things apart...

SKTP · « **Reply #42 on:** December 02, 2009, 01:54:14 PM »

Currently, I'd like to drive it off a large cliff

andy750 · « **Reply #43 on:** December 02, 2009, 02:02:37 PM »

Just curious but after reading through this thread how do you know its your transmission and not 1) your clutch? 2) a stuck gear shifter? or 3) something else? chain/sprockets etc

Are you 100% sure its the tranny? Very rare for it just to...and what if you take the engine out, have it apart and nothing is wrong? Get a second opinion first if you are unsure.

cheers
Andy

SKTP · « **Reply #44 on:** December 02, 2009, 02:11:34 PM »

Thanks Andy, it sure sounds and feels like the tranny (keep in mind this is the only bike I have ever owned).

I did have a local mechanic ride it. Hold seemed to agree that it was the first gear or shifter forks. It basically has half a release of the clutch of first then slips and makes a terrible grinding sound. There are pings and *tinks* at a neutral idle. When I cut the motor it makes terrible grinding sounds (only sometimes). And yesterday for the first time ever it got stuck between First and Neutral or Second and took many kick on the shifter to get it moving the wheel again...

All that being said, I had it up to 100mph today on a 20 mile freeway run to the ear doctor. Once its in second, everything seems to be fine.

bryanj · « **Reply #45 on:** December 03, 2009, 08:16:11 AM »

I'd be paranoid running high speed with a dodgy box that something would give out, like a tooth, and jam the box solid so all i saw was
Ground
Sky
Ground
Sky
OW!

MCRider · « **Reply #46 on:** December 03, 2009, 08:21:20 AM »

Quote from: bryanj on December 03, 2009, 08:16:11 AM

I'd be paranoid running high speed with a dodgy box that something would give out, like a tooth, and jam the box solid so all i saw was
Ground
Sky
Ground
Sky
OW!

I was thinking the same. I've lost track of all the trans threads, but someone had one with the broken dogs from the gears laying in the box. Scares me and I'm not afraid of anything.

andy750 · « **Reply #47 on:** December 03, 2009, 08:46:19 AM »

Very good description and thanks for that - I now agree you seem to have a tranny problem! It sounds a lot like my old tranny problem on my K2. The grinding in first gear followed by nothing wrong after 2nd gear...have you checked your oil for metal filings yet? If not drain the oil from the sump and look for shiny bits of metal.

My problem was a busted final gear bearing and to replace it meant splitting the cases.

good luck with the oil check! (do the filter at the same time to check for shavings in there)

cheers
Andy

SKTP · « **Reply #48 on:** December 03, 2009, 09:51:20 AM »

I just did and oil and oil filter change (about 1600 miles since the last one) there was a little black grit in the filter casing, but not a crazy amount...

Nothing to add to the list? How about; New valve springs?

MCRider · « **Reply #49 on:** December 03, 2009, 09:53:23 AM »

Quote from: SKTP on December 03, 2009, 09:51:20 AM

I just did and oil and oil filter change (about 1600 miles since the last one) there was a little black grit in the filter casing, but not a crazy amount...

Nothing to add to the list? How about; New valve springs?

You wouldn't need new valve springs unless you were installing a big bumo cam. Stockers are good forever with a stock cam.

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Author Topic: So while driving to work today...transmission fun! - total engine rebuild fun! (Read 9539 times)

EverettShadowbrook